Machines are known which automatically fill such cups and carry out ancillary operations, including the covering and sealing of the containers, on a mass-production basis with the aid of a conveyor having seats in the form of recesses designed to receive the containers and to move them past a number of operating stations which are synchronized with the conveyor motion. These stations generally include a loading station depositing empty containers in the several recesses, a dispensing station introducing metered quantities of the product into each container moving past, a capping station supplying a lid to each filled container, and a sealing station for bonding the lid to the container. The operating speed of a metering dispenser is limited by mechanical as well as fluidic considerations. If the product to be dispensed is heavy cream or yogurt, for example, high supply velocities may lead to foaming and thereby to a wetting of the container rim interfering with the subsequent heat-sealing operation. The latter operation, with containers of thermoplastic resin, also requires a minimum cycle length in order to let the material of the container and its lid reach the necessary fusion temperature; attempts to accelerate this process by more intensive heating may result in an inadmissible deformation of the container mouth and/or a partial vaporization of the resin, preventing a hermetic closure. Thus, the common work cycle of the various synchronized operating stations cannot be significantly foreshortened with currently available techniques.
In order to increase the output rate of such an apparatus, therefore, it is the practice to let each station act concurrently upon a multiplicity of containers during every work cycle. For this purpose it is customary to arrange the container-receiving recesses of the conveyor in rows transverse to its direction of motion, each operating station serving all the recesses of a row aligned with it during a given work cycle. However, the length of each row and therefore the number of containers served in any cycle is also subject to physical restrictions. With a conveyor having 12 recesses per row and advancing by 30 steps per minute, for example, the theoretical output would be close to 22,000 containers per hour, yet in practice this rate of production is hardly ever achieved since the middle positions of a row are almost out of reach of the operating personnel so that the reloading of cup, lid and product feeders as well as adjustments such as the setting of terminal dates are difficult to perform in a central conveyor zone. In such a machine, therefore, an operator will frequently modify the existing equipment to leave the middle recesses of the several rows unoccupied.